EPON助力宽带业务拓展

技术支撑能力强大 实现千兆比特率的高速接入 EPON对于业务的强大支撑能力得益于其高带宽的提供能力.基于EPON的技术可以实现千兆比特率的高速接入.这样的高带宽是其它接入技术所难以达到的.EPON带宽共享特性和系统的统一性使其在管理和业务供给方面也非常灵活.在实际应用中,EPON能充分利用资源,减少运行和维护费用,节省运营商的长期投资成本.     

以太网无源光网络中的时间标签法测距

基于千兆以太网的无源光网络将千兆以太网与无源光纤接入的优势相结合,实现低成本的高速、远距离接入。针对EPON系统上行链路多个ONU共享带宽的树型拓扑结构,为实现EPON系统上行TDMA接入,提出了时间标签法测距方案,论述了方案的可行性并指出其优点。     

新的光纤接入系统

ＮＴＴ开发了新的光纤接入系统(俗称π系统),计划1997年底开始在日本全面引入。此系统的核心为光ＰＤＳ系统,多个用户共享ＮＴＴ大楼与靠近用户的光纤网络单元之间的一根光缆;每个光纤网络单元可容纳10个用户。为降低成本,光ＰＤＳ系统采用“分光器”,使多个光纤网络单元共享一个用户线终端(ＳＬＴ)。在需求分散的居民区和从电线杆上传统系统的配线点在商业区引入此系统对未来高速宽带业务有以下好处:以15Ｍｂ/ｓ速率接入高速数字租用线路;为高速/宽带业务提供专用光缆可降低成本,电话业务使用相同管道;光缆接至用户最近的电线杆处,铺设光缆…     

GSM升级高速宽带在农村市场中的应用

农村市场宽带接入不足一直是困扰运营商全业务竞争的难题之一。G SM（全球移动通信系统）升级高速宽带通过G SM技术演进,利用现有的基站、天馈资源,提供高速共享的无线宽带接入能力,通过专用无线终端接入设备〔CPE（用户驻地设备）〕提供用户侧的无线或有线接入,可以快速解决农村宽带接入不足的问题,提升运营商的全业务竞争能力。     

宽带无线接入

随着世界各地区电信业务提供者利用高速光纤骨干网承载话音、数据和INTERNET业务，没有先进接入基础设施的运营者将不可能在网路通信中取得优势。信息共享已经成为商业基础。INTERNET、电子商务和其它数据技术的快速发展和接受已经改变世界通信方式。电信运营商如果不能充分运用这些新技术，将在竞争中处于劣势。宽带无线接入是近年来新兴的一种接入手段，为通信公司提供了经济和简便的解决方案。     

普天TD-SCDMA HSDPA解决方案

1 TD—SCDMA HSDPA概述 与R99和R4技术相比,HSDPA引入了高速下行共享信道HS—DSCH。在NodeB中,采用了一个新的媒体接入控制子层（MAC—hs）来控制高速数据传输,使用5msTTI,并采用多种核心关键技术：     

一种基于OCDMA技术实现局域网随机接入的方法

局域网信道共享时，有限的信道只能允许有限的用户接入，而且由于存在多用户间的干扰，不能实现真正的随机接入，因此存在扩容限制。光码分多址（OCDMA）技术可提供宽带宽和实现多址。OCDMA采用单极性扩频正交编码对输入信息进行编码，使得低速率的数据信息复用为高速率的光脉冲序列进行传输或解复用，实现多用户的信道共享和随机异步接入以及高速透明的数据通信，有效消除多用户信道间的干扰。基于OCDMA技术组建局域网络，采用智能多级网关对系统进行扩容，能实现多用户真正的随机接入。     

基于动态门限的HS-SCCH外环功率控制算法

高速下行分组接入技术(HSDPA)通过使用自适应调制编码、混合自动重传请求、快速调度等关键技术,来提高下行数据的传输速率。为了充分利用这些技术,必须保证Node B和用户设备(UE)之间可靠的信息交换。高速共享控制信道(HS-SCCH)承载着高速下行共享信道(HS-DSCH)解调所需的关键信令,因此,HS-SCCH功率控制显得尤其重要。本文在分析HS-SCCH的内环和外环功率控制算法的基础上,提出了一种基于动态门限的HS-SCCH的外环功率控制算法。链路级仿真表明,提出的算法具有优良的性能。     

基于CQI的HS—SCCH的功控算法

文中介绍了高速下行链路分组接入技术（HSDPA）的高速共享控制信道（HS—SCCH）的一种功率控制算法：基于信道质量指示（CQI）的功率控制算法．介绍了该算法的原理：通过计算机仿真，分析了该算法的性能．从仿真结果可以看出，基于CQI的HS-SCCH功率控制算法适用于HSDPA。     

Ad hoc网络接入Internet的连接共享机制

方便地接入Internet,对于发挥Adhoc网络的潜能至关重要。首先说明了Adhoc网络接入Internet面临的问题,然后介绍了一种基于连接共享机制使Adhoc网络接入Internet的网络配置,接着详细阐述了连接共享的过程和相关机制,并对连接共享协议的开销进行了分析。     

关于Cache在移动互联网的应用与分析

Cache是一种互联网高速缓存系统,是目前移动运营商提升数据业务下载速率最有效的手段之一。它通过分析和研究互联网业务的请求链接URL,采用被动缓存技术,对热点业务的资源内容进行缓存和重定向转发,将外网资源迁移至网内进行本地化缓存,达到缩短终端用户下载目标资源的路径长度的目的。对P2P文件传输、HTTP文件下载、Web页面浏览以及在线视频播放等各种应用实现网内缓存加速,能提升30%左右的下载速率。同时Cache系统中的重定向功能,也可对移动数据业务访问成功率带来2.2%的提升。     

Mobile Hotspot Network System for High‐Speed Railway Communications Using Millimeter Waves

We propose a millimeter wave (MMW)‐based mobile hotspot network (MHN) system for application in high‐speed railways that is capable of supporting a peak backhaul link throughput of 1 Gbps per train at 400 km/h. The MHN system can be implemented in subways and high‐speed trains to support passengers with smart devices and provide access to the Internet. The proposed system can overcome the inherent high path loss in MMW through system designs and high antenna gains. We present a simulation of the system performance that shows that a fixed beamforming strategy can provide high signal‐to‐interference‐plus‐noise‐ratio similar to those of an adaptive beamforming strategy, with the exception of 15% of the train path in which the network can use link adaptation with low‐order modulation formats or trigger a handover to maintain the connection. We also demonstrate the feasibility of the MHN system using a test bed deployed in Seoul subway line 8. The backhaul link throughput varies instantaneously between 200 Mbps and 500 Mbps depending on the SNR variations while the train is running. During the field trial, the smartphones used could make connections through offloading.     

Dynamic parallel access to replicated content in the Internet

Popular content is frequently replicated in multiple servers or caches in the Internet to offload origin servers and improve end-user experience. However, choosing the best server is a nontrivial task and a bad choice may provide poor end user experience. In contrast to retrieving a file from a single server, we propose a parallel-access scheme where end users access multiple servers at the same time, fetching different portions of that file from different servers and reassembling them locally. The amount of data retrieved from a particular server depends on the resources available at that server or along the path from the user to the server. Faster servers deliver bigger portions of a file while slower servers deliver smaller portions. If the available resources at a server or along the path change during the download of a file, a dynamic parallel access automatically shifts the load from congested locations to less loaded parts (server and links) of the Internet. The end result is that users experience significant speedups and very consistent response times. Moreover, there is no need for complicated server selection algorithms and load is dynamically shared among all servers. The dynamic parallel-access scheme presented does not require any modifications to servers or content and can be easily included in browsers, peer-to-peer applications or content distribution networks to speed up delivery of popular content.     

ARC: the analytical rate control scheme for real-time traffic in wireless networks

Next-generation wireless Internet (NGWI) is expected to provide a wide range of services including real-time multimedia to mobile users. However, the real-time multimedia traffic transport requires rate control deployment to protect shared Internet from unfairness and further congestion collapse. The transmission rate control method must also achieve high throughput and satisfy multimedia requirements such as delay or jitter bound. However, the existing solutions are mostly for the wired Internet, and hence, they do not address the challenges in the wireless environments which are characterized by high bit error rates. In this paper, a new analytical rate control (ARC) protocol for real-time multimedia traffic over wireless networks is presented. It is intended to achieve high throughput and multimedia support for real-time traffic flows while preserving fairness to the TCP sources sharing the same wired link resources. Based on the end-to-end path model, the desired behavior of a TCP source over lossy links is captured via renewal theory. The resulting asymptotic throughput equation is designated as the driving equation for the proposed rate control method. Performance evaluation via simulation experiments reveals that ARC achieves high throughput and meets multimedia traffic expectations without violating good citizenship rules for the shared Internet.     

ADSL宽带接入技术及实际应用

ＡＤＳＬ是一种颇为看好的宽带接入过渡技术,它可以在保护现有投资的同时,满足当前用户的宽带业务需求。本文给出了ＡＤＳＬ的系统模型,并结合我国国情分析了该技术的优缺点,介绍了可利用ＡＤＳＬ开展的非对称业务,如视频点播、高速Ｉｎｔｅｒｎｅｔ接入、远程监控监测、高速ＬＡＮ互联、居家办公等。     

构架中国的“数码大厦”

因特网数据中心（IDC）已成为承截各种模式电子商务的基本设施。作为新的服务模式,IDC重新创造了因特网服务的价值链,形成了不同分工的因特网服务提供商。高速、安全是IDC提供高质服务的两个方面。IDC改变了传统客户/服务器的服务模式,将ICP的访问服务器从边缘移到了高速核心骨干网中心交换点,从而减少了不必要的承载负担,提高了有效速度。而多节点数据中心通过容灾备份保证了数据安全,是未来发展趋势。     

Seamless LTE connectivity in high‐speed trains

High‐speed train (HST) is revitalizing the train as a preferred mid‐range transportation system. The provision of broadband Internet connectivity onboard trains is one of the key challenges in the competition among train operators. Unprecedented spectral efficiency and data rates (up to 100Mbps in high mobility) of the Universal Mobile Telecommunications System long‐term evolution (LTE) are expected to offer the solution for high‐speed Internet access onboard in HSTs. Massive wireless access and frequent handovers (HOs) of a large number of users might potentially cause service interruptions, and this, in turn, degrades intolerably the quality of experience (QoE) of users' onboard Internet access. In this paper, we propose a solution based on distributed antenna system that combines directional and omni‐directional antennas as train‐to‐ground radio‐access terminals (T‐RATs) and LTE femtocells in each carriage. Directional antennas are deployed at both ends of the HST to provide multi‐cell access by diversifying the HOs over multiple LTE cells. This mechanism virtually elongates the train size by connecting the front and rear carriages' T‐RATs to the faraway eNodeBs and augmenting the number of cells the HST can be simultaneously connected to. An ad hoc distributed load‐balancing mechanism that consists in offloading backlogged packets to the on‐service T‐RATs is mandatorily paired with multi‐cell access scheme to tie up with the request of seamless onboard Internet service at high QoE level. Copyright © 2015 John Wiley & Sons, Ltd.     

通用ADSL技术

本文首先介绍了ＵＡＤＳＬ（通用ＡＤＳＬ）的产生背景，接着给出了ＵＡＤＳＬ的结构、技术问题及其解决方法，最后介绍了Ａｌｃａｔｅｌ的多业务接入平台Ｌｉｔｅｓｐａｎ－１５４０。     

A new model of bandwidth growth estimation based on the gompertz curve: application to optical access networks

This paper describes the analysis of the evolution of Internet service access for the residential sector with the purpose of obtaining an expression to make predictions about its increase over the next ten years. The models derived from a traditional industrial economy are no longer valid to calculate the evolution of Internet service access. As such, the authors of this paper propose and test a new model to calculate the increase in the percentage of Internet users based on the concepts of a network economy. The new model, combined with the tendency of modem speed evolution, produces a new equation to calculate the bandwidth growth in optical access networks. This way of calculating the bandwidth growth of the access networks is independent of the authors' knowledge of future Internet services. Application of the model to a simulated geographical area is shown.     

Doing double duty: power-line communications

In 2001, the German Minister of Economy passed several laws, allocating frequencies up to 30 MHz for the introduction of new technologies, such as power-line communications (PLC). The proposed PLC systems are designed to increase data to megabits per second, offering high speed Internet access. Interference to amateur radio operators and shortwave listeners is considered